The present invention relates to a multi-component oil control piston ring for use in an internal combustion engine. More particularly, the invention relates to a particular ring structure that prevents rotation of the ring within the ring groove.
In a piston engine of the horizontally opposed type, when the engine is horizontal, the location of the ring gap is generally immaterial. If, however, the engine is inclined and the ring gap is located on the lower portion of the cyclinder, lubricating oil may flow through the gap and collect in the combustion chamber. If the engine is started in that condition, the lubricating oil in the combustion chamber burns and the residual carbon contaminates the interior surface of the combustion chamber. This residue prevents the complete combustion of fuel in the combustion chamber and thereby gives rise to a reduction in the output of the engine. In addition, there is a waste of lubricating oil which may also result in its depletion from the lubrication system. In such an event, there is every likelihood that seizure may eventually occur between the piston ring and the cylinder wall.
In order to overcome these drawbacks, it has hitherto been conventional to employ the ring configuration shown in FIGS. 3 and 4. Referring to FIG. 3, one of the ends of a corrugated expander-spacer 1 defining a joint 11 in the expander-spacer has an extension 12 which is engaged in a drain hole (not shown) in the piston ring groove. This prevents the expander-spacer from rotating in the groove.
Referring to FIG. 4, a thin upper cylinder engaging ring 2 member has a projection 21 which is engageable in one of the open spaces defined by the expander-spacer 1. This prevents the upper ring member from rotating in relation to the expander-spacer 1.
The conventional method as hereinabove described has, however, the disadvantage of being inapplicable when the ring member 2 is formed from a brittle material. It is also complicated, as it involves two different ways for holding the expander-spacer and the ring members to prevent rotation.
Under these circumstances, it is an object of this invention to provide a steel oil control ring which can be held against rotation by only a single method which is applicable to even a cylinder engaging ring member formed from a brittle material.